A. Technical Field
The present invention relates to a novel (meth)acrylate ester-based resin composition.
In more detail, the present invention relates to a novel (meth)acrylate ester-based resin composition which, for example, exhibits various good properties such as weather resistance, heat resistance, water resistance, acid resistance, alkali resistance, warm water resistance, impact resistance, processability, flexibility, hardness, elongation, transparency, luster, fleshy property, mirroring property, pigment dispersibility, and driability when being used for various uses such as coating agents (e.g. for films, plastics, glass, paper, fibers, leather), pressure sensitive adhesives, and adhesives in addition to various paints (e.g. lacquer type paints, curing type paints) such as paints for building exteriors, paints for building materials, paints for metals, paints for steel-made furniture, paints for plastics, heavy anticorrosive paints, waterproof paints for roofs, paints for cars, paints for car parts, and paints for electrical appliances.
B. Background Art
(Meth)acrylic resin paints which contain crosslinking agents are superior to noncrosslinking type acrylic resin paints in respect to such as weather resistance, heat resistance, water resistance, alkali resistance, warm water resistance, impact resistance, processability, and flexibility, and are therefore used in wide fields of such as building materials, woodworking, roofing tiles, metals, paper, plastics, glass, and fibers, and desired to be still more excellent in respect to the above properties.
Coating films of paints which are used in such as architectural fields and building fields have so far had problems of undergoing such as hazing, discoloring, blistering, or cracking due to such as ultraviolet rays, heat, alkali components as eluted from substrates, and recent acid rain because of being exposed to wind, rain, or sunlight for a long time. Therefore, in the case where durability and weather resistance for a long time are needed, it is effective to use such as solvent type fluororesin paints or acrylic silicone resin paints. However, there are problems in that these paints increase costs so much as to be usable actually for limited uses only.
In addition, cyclohexyl (meth)acrylate was particularly favorable as a polymerizable unsaturated monomer having the low hygroscopic functional group effective for achieving the high weather resistance. However, in the case where the cyclohexyl (meth)acrylate content of polymers is too high, the resultant coating films are inferior in such as flexibility, processability, and adhesion. Therefore, there are problems in that the current level is still insufficient, so the range of the actual use of the cyclohexyl (meth)acrylate is also limited.
A. Object of the Invention
An object of the present invention is to provide a novel (meth)acrylate ester-based resin composition which, for example, exhibits various good properties such as weather resistance, heat resistance, water resistance, acid resistance, alkali resistance, warm water resistance, impact resistance, processability, flexibility, hardness, elongation, transparency, luster, fleshy property, mirroring property, pigment dispersibility, and driability when being used, for example, as crosslinking type paints, adhesives, pressure sensitive adhesives, and fiber-processing materials, and has so low a resin viscosity as to be utilizable as a resin for coping with environmental pollution of such as low-VOC paints.
B. Disclosure of the Invention
The present inventors diligently studied to solve the above problems. As a result, they have completed the present invention by finding out that the above problems could be solved by a (meth)acrylate ester-based resin composition comprising a (meth)acrylate ester-based polymer and a crosslinking agent wherein the (meth)acrylate ester-based polymer is obtained by a process including the step of polymerizing a monomer component including a specific (meth)acrylate ester as an essential component wherein the (meth)acrylate ester possesses an alkylcyclohexylalkyl group as an introduced ester group.
That is to say, a (meth)acrylate ester-based resin composition, according to the present invention, comprises a (meth)acrylate ester-based polymer (I) and a crosslinking agent, wherein the (meth)acrylate ester-based polymer is obtained by a process including the step of polymerizing a monomer component including a polymerizable unsaturated monomer (a) as an essential component and has a reactive group wherein the polymerizable unsaturated monomer (a) is an alkylcyclohexylalkyl ester of (meth)acrylic acid, and wherein the crosslinking agent has at least two functional groups that are reactable with the reactive group. More specifically, the alkylcyclohexylalkyl ester of (meth)acrylic acid, as referred to in the present invention, has an alkyl group on the cyclohexyl group.
These and other objects and the advantages of the present invention will be more fully apparent from the following detailed disclosure.
((Meth)acrylate Ester-based Polymer)
The (meth)acrylate ester-based polymer (I), which is an essential component of the (meth)acrylate ester-based resin composition according to the present invention, is a polymer which is obtained by a process including the step of polymerizing a monomer component including a polymerizable unsaturated monomer (a) as an essential component wherein the polymerizable unsaturated monomer (a) is an alkylcyclohexylalkyl ester of (meth)acrylic acid, and which has a reactive group. Incidentally, the cyclohexyl group in the molecular structure of the aforementioned polymerizable unsaturated monomer (a) has a substituent.
In addition, the aforementioned alkylcyclohexylalkyl ester of (meth)acrylic acid, which is an essential monomer component of the (meth)acrylate ester-based polymer (I) that is an essential component of the resin composition according to the present invention, is favorably denoted by the following general formula (1): 
R1 in the specific polymerizable unsaturated monomer (a) as denoted by the aforementioned general formula (1) is a hydrogen atom or methyl group.
R2 in the specific polymerizable unsaturated monomer (a) as denoted by the aforementioned general formula (1) is a hydrogen atom or organic residue. In the case where the R2 is an organic residue, favorable examples include 1-cyclohexylethyl (meth)acrylate (which might be referred to as cyclohexyl(methyl)methyl (meth)acrylate) although there is no especial limitation thereto. In addition, n is an integer of 1 to 4.
R3 in the specific polymerizable unsaturated monomer (a) as denoted by the aforementioned general formula (1) is an organic residue on the cyclohexyl group. In addition, m is an integer of 1 or 2. The case of m=1 denotes monosubstitution, and the case of m=2 denotes disubstitution. In this case, R3 may be a substituent at any position if it is on the cyclohexyl group. In addition, one kind of substituent may exist in one or more places, or at least two kinds of substituents may exist in one or more places. Examples of R3, which is an organic residue, include linear, branched, or cyclic alkyl groups having 1 to 10 carbon atoms, hydroxyalkyl groups having 1 to 5 carbon atoms, alkoxyalkyl groups having 1 to 5 carbon atoms, acetoxyalkyl groups having 1 to 5 carbon atoms, and halogenated (e.g. chlorinated, brominated, or fluorinated) alkyl groups having 1 to 5 carbon atoms. Favorably used of them are alkyl groups having 1 to 4 carbon atoms, hydroxyalkyl groups having 1 to 2 carbon atoms, alkoxyalkyl groups having 1 to 2 carbon atoms, and acetoxyalkyl groups having 1 to 2 carbon atoms. As is mentioned above, the above R3 may be a substituent at any position if it is on the cyclohexyl group, but favorably the position of R3 is the 3- or 4-numbered position. However, the above R3 is defined as not including the epoxy-substituent structure which is seen in such as 3,4-epoxycyclohexylmethyl (meth)acrylate and 3,4-epoxycyclohexylethyl (meth)acrylate. In other words, the alicyclic epoxy ring structure is not included in the cyclohexyl group structure in the aforementioned general formula (1).
Although not especially limited, favorable specific examples of the specific polymerizable unsaturated monomer (a) as denoted by the aforementioned general formula (1) include 4-methylcyclohexylmethyl (meth)acrylate, 4-ethylcyclohexylmethyl (meth)acrylate, 4-propylcyclohexylmethyl (meth)acrylate, 4-butylcyclohexylmethyl (meth)acrylate, 4-methoxycyclohexylmethyl (meth)acrylate, 4-acetoxymethylcyclohexylmethyl (meth)acrylate, 3-methylcyclohexylmethyl (meth)acrylate, 3-ethylcyclohexylmethyl (meth)acrylate, 3-propylcyclohexylmethyl (meth)acrylate, 3-butylcyclohexylmethyl (meth)acrylate, 3-methoxycyclohexylmethyl (meth)acrylate, 3-acetoxymethylcyclohexylmethyl (meth)acrylate, 3-hydroxymethylcyclohexylmethyl (meth)acrylate, 4-methylcyclohexylethyl (meth)acrylate, 4-ethylcyclohexylethyl (meth)acrylate, 4-propylycyclohexylethyl (meth)acrylate, 4-butylcyclohexylethyl (meth)acrylate, 4-methoxycyclohexylethyl (meth)acrylate, 4-acetoxymethylcyclohexylethyl (meth)acrylate, 4-hydroxymethylcyclohexylethyl (meth)acrylate, 3-methylcyclohexylethyl (meth)acrylate, 3-ethylcyclohexylethyl (meth)acrylate, 3-propylcyclohexylethyl (meth)acrylate, 3-butylcyclohexylethyl (meth)acrylate, 3-methoxycyclohexylethyl (meth)acrylate, 3-acetoxymethylcyclohexylethyl (meth)acrylate, 3-hydroxymethylcyclohexylethyl (meth)acrylate, 4-methylcyclohexylpropyl (meth)acrylate, 4-ethylcyclohexylpropyl (meth)acrylate, 4-methoxycyclohexylpropyl (meth)acrylate, 4-acetoxymethylcyclohexylpropyl (meth)acrylate, 4-hydroxymethylcyclohexylpropyl (meth)acrylate, 3-methylcyclohexylpropyl (meth)acrylate, 3-ethylcyclohexylpropyl (meth)acrylate, 3-methoxycyclohexylpropyl (meth)acrylate, 3-acetoxymethylcyclohexylpropyl (meth)acrylate, 3-hydroxymethylcyclohexylpropyl (meth)acrylate, 4-methylcyclohexylbutyl (meth)acrylate, 4-ethylcyclohexylbutyl (meth)acrylate, 4-methoxycyclohexylbutyl (meth)acrylate, 4-acetoxymethylcyclohexylbutyl (meth)acrylate, 4-hydroxymethylcyclohexylbutyl (meth)acrylate, 3-methylcyclohexylbutyl (meth)acrylate, 3-ethylcyclohexylbutyl (meth)acrylate, 3-methoxycyclohexylbutyl (meth)acrylate, 3-acetoxymethylcyclohexylbutyl (meth)acrylate, 3-hydroxymethylcyclohexylbutyl (meth)acrylate, 2-methyl-1-cyclohexylmethyl (meth)acrylate, 2,3-dimethyl-1-cyclohexylmethyl (meth)acrylate, 2,4-dimethyl-1-cyclohexylmethyl (meth)acrylate, 2,6-dimethyl-1-cyclohexylmethyl (meth)acrylate, 2-phenyl-1-cyclohexylmethyl (meth)acrylate, 2-phenyl-3-methyl-1-cyclohexylmethyl (meth)acrylate, 2-phenyl-4-methyl-1-cyclohexylmethyl (meth)acrylate, 2-phenyl-5-methyl-1-cyclohexylmethyl (meth) acrylate, and 2-phenyl-6-methyl-1-cyclohexylmethyl (meth)acrylate. Of these, those which include isomers may be each isomer alone and/or mixtures of isomers. Favorably used of the above polymerizable unsaturated monomers (a) are 4-methylcyclohexylmethyl (meth)acrylate, 4-ethylcyclohexylmethyl (meth)acrylate, 4-methoxycyclohexylmethyl (meth)acrylate, 4-acetoxymethylcyclohexylmethyl (meth)acrylate, 3-methylcyclohexylmethyl (meth)acrylate, 3-ethylcyclohexylmethyl (meth)acrylate, 3-acetoxymethylcyclohexylmethyl (meth)acrylate, 3-hydroxymethylcyclohexylmethyl (meth)acrylate, 4-methylcyclohexylethyl (meth)acrylate, 3-methylcyclohexylethyl (meth)acrylate, 4-methylcyclohexylpropyl (meth)acrylate, 3-methylcyclohexylpropyl (meth)acrylate, 4-methylcyclohexylbutyl (meth)acrylate, and 3-methylcyclohexylbutyl (meth)acrylate.
The (meth)acrylate ester-based polymer (I), which is an essential component of the resin composition according to the present invention, is obtained by a process including the step of polymerizing a monomer component including the above specific polymerizable unsaturated monomer (a) of the aforementioned general formula (1) as an essential component. The content of the polymerizable unsaturated monomer (a) in the aforementioned monomer component is favorably not less than 5 weight %, more favorably not less than 10 weight %, still more favorably not less than 20 weight %, yet still more favorably not less than 25 weight %, particularly favorably not less than 30 weight %, most favorably not less than 35 weight %, in view of the properties of the resulting aforementioned (meth)acrylate ester-based polymer and further the properties of the finally obtained resin composition according to the present invention. In addition, the content of the polymerizable unsaturated monomer (a) in the aforementioned monomer component is favorably not more than 95 weight %, more favorably not more than 90 weight %, still more favorably not more than 85 weight %, for enhancing the weather resistance and getting better such as property balance between impact resistance and flexibility, as concerned with processability, of the finally obtained resin composition according to the present invention.
Favorable examples of the process for producing the specific polymerizable unsaturated monomer (a) of the aforementioned general formula (1) include: {circle around (1)} a production process comprising the step of carrying out a reaction between (meth)acrylic acid and an alcohol as denoted by the below-mentioned general formula (2); {circle around (2)} a production process comprising the step of carrying out a reaction between a (meth)acryloyl halide and an alcohol as denoted by the below-mentioned general formula (2); {circle around (3)} a production process comprising the step of carrying out a reaction between (meth)acrylic anhydride and an alcohol as denoted by the below-mentioned general formula (2); {circle around (4)} a production process comprising the step of carrying out a reaction between a (meth)acrylic acid alkyl ester and an alcohol as denoted by the below-mentioned general formula (2); and {circle around (5)} a production process comprising the step of carrying out a reaction between (meth)acrylic acid and a carboxylate ester as denoted by the below-mentioned general formula (3). However, there is no especial limitation to these production processes. Of these production processes, particularly, production processes {circle around (1)}, {circle around (4)}, and {circle around (5)} are favorable for such as economy. 
wherein:
R2 is a hydrogen atom or organic residue;
R3 is an organic residue on the cyclohexyl group;
R4 is a hydrogen atom or organic residue;
m is an integer of 1 or 2; and
n is an integer of 1 to 4. However, the above R3 is defined as not including the epoxy substituent which is seen in such as 3,4-epoxycyclohexylmethyl (meth)acrylate and 3,4-epoxycyclohexylethyl (meth)acrylate.
As is mentioned above, the (meth)acrylate ester-based polymer (I) in the present invention comprises the monomer component including the above polymerizable unsaturated monomer (a) as an essential component wherein the polymerizable unsaturated monomer (a) is an alkylcyclohexylalkyl ester of (meth)acrylic acid particularly of the cyclohexylalkyl esters of (meth)acrylic acid. Therefore, not only this polymer (I) but also the below-mentioned (meth)acrylate ester-based resin composition, comprising this polymer (I) as an essential component, exhibits the enhanced properties, which are not especially limited, but can favorably be exemplified by the following 1) to 3). 1) In the case where the polymer (composition) is used as a resin (composition) for paints, the processability and the toughness such as impact resistance of the coating film are enhanced. 2) The increase of the solubility into a solvent provides enablement for easy achievement of the decrease of the resin viscosity and the increase of the resin solid content, particularly, provides enablement for utilization for such as a resin (composition) for high-solid paints as a resin (composition) for paints of types coping with the environment and a resin (composition) for weak solvent type paints involving the use of low polar solvents. 3) In the case where the polymer (composition) is used as a resin (composition) for paints, such as water resistance and weather resistance of the coating film are enhanced, and further, the properties which are demanded to clear top paints for cars such as resistance to acid rain are enhanced.
The (meth)acrylate ester-based polymer (I) in the present invention favorably has a reactive group. When this (meth)acrylate ester-based polymer (I) is produced, the process for introducing the above reactive group is not especially limited, but favorable examples thereof include: (1) a process involving the use of the polymerizable unsaturated monomer (a) and a polymerizable unsaturated monomer (b) which is another polymerizable unsaturated monomer copolymerizable with the monomer (a) and has a reactive group; and (2) a process comprising the steps of polymerizing the monomer component including the polymerizable unsaturated monomer (a) as an essential component, and then carrying out such as an addition reaction of a compound having a reactive group, thereby introducing the reactive group. Either one of these processes or a plurality thereof may be used. In addition, in the case where the reactive group to be introduced is such as a hydroxyl group, an acidic functional group (e.g. a carboxyl group, a sulfonic acid group, a phosphoric acid group), an epoxy group, a hydrolyzable silyl group, a silanol group, an active carbonyl group, an oxazoline group, or an isocyanate group, it is effective to use the process (1) above.
In the case where the process (1) above is used as the process for preparing the (meth)acrylate ester-based polymer (I) in the present invention, it is favorable to polymerize monomer components including the polymerizable unsaturated monomer (a) and the polymerizable unsaturated monomer (b) having a reactive group as essential components in order that the (meth)acrylate ester-based polymer (I) can have the reactive group. Specifically, in the case where the (meth)acrylate ester-based polymer (I) in the present invention is obtained, it is favorable to copolymerize the polymerizable unsaturated monomer (a) and the polymerizable unsaturated monomer (b) having a reactive group or to copolymerize the polymerizable unsaturated monomer (a), the polymerizable unsaturated monomer (b) having a reactive group, and another polymerizable unsaturated monomer (c) which is copolymerizable with at least one of these monomers.
The above polymerizable unsaturated monomer (b) having a reactive group is not especially limited, but favorable examples thereof include: (i) polymerizable unsaturated monomers having the alcoholic hydroxyl group; (ii) polymerizable unsaturated monomers having the acidic functional group; (iii) polymerizable unsaturated monomers having the epoxy group; (iv) polymerizable unsaturated monomers having the isocyanate group; (v) polymerizable unsaturated monomers having the active carbonyl group; and (vi) polymerizable unsaturated monomers having the oxazoline group. These may be used either alone respectively or in combinations with each other. In addition, specific examples of each of these monomers (i) to (vi) are hereinafter enumerated, but there is no especial limitation thereto.
Favorable examples of the (i) polymerizable unsaturated monomers having the alcoholic hydroxyl group include hydroxyl-group-containing (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, methyl(xcex1-hydroxymethyl) acrylate, ethyl(xcex1-hydroxymethyl) acrylate, butyl(xcex1-hydroxymethyl) acrylate, caprolactone-modified hydroxy(meth)acrylate (trade name: Placcel F series, produced by Daicel Chemical Industries, Ltd.), 4-hydroxymethylcyclohexylmethyl (meth)acrylate, ethylene glycol mono(meth)acrylate, diethylene glycol mono(meth)acrylate, tetraethylene glycol mono(meth)acrylate, propylene glycol mono(meth)acrylate, dipropylene glycol mono(meth)acrylate, and tetrapropylene glycol mono(meth)acrylate. These may be used either alone respectively or in combinations with each other.
Favorable examples of the (ii) polymerizable unsaturated monomers having the acidic functional group include:
carboxyl-group-containing unsaturated monomers such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid, citraconic acid, maleic anhydride, monomethyl maleate, monobutyl maleate, monomethyl itaconate, monobutyl itaconate, vinylbenzoic acid, monohydroxyethyl oxalate (meth)acrylate, dimethyl maleate, diethyl maleate, dibutyl maleate, dimethyl fumarate, diethyl fumarate, dibutyl fumarate, carboxyl-group-terminated caprolactone-modified acrylate (trade name: Placcel FA series, produced by Daicel Chemical Industries, Ltd.), and carboxyl-group-terminated caprolactone-modified methacrylate (trade name: Placcel FMA series, produced by Daicel Chemical Industries, Ltd.);
metal salts and amine salts of the carboxyl-group-containing unsaturated monomers, such as sodium acrylate and sodium methacrylate;
sulfonic-acid-group-containing unsaturated monomers such as vinylsulfonic acid, styrenesulfonic acid, and sulfoethyl (meth)acrylate; and
acidic-functional-group-containing polymerizable unsaturated monomers, for example, acidic phosphate ester-based unsaturated monomers such as 2-(meth)acryloyloxyethyl acid phosphate, 2-(meth)acryloyloxypropyl acid phosphate, 2-(meth)acryloyloxy-3-chloro-propyl acid phosphate, and 2-(meth)acryloyloxyethyl phenyl phosphate.
These may be used either alone respectively or in combinations with each other.
Favorable examples of the (iii) polymerizable unsaturated monomers having the epoxy group include glycidyl (meth)acrylate, xcex1-methylglycidyl acrylate, glycidyl allyl ether, oxocyclohexylmethyl (meth)acrylate, 3,4-epoxycyclohexylmethyl acrylate (trade name: CYCLOMER A200, produced by Daicel Chemical Industries, Ltd.), xcex1-methylglycidyl methacrylate (trade name: M-GMA, produced by Daicel Chemical Industries, Ltd.), and 3,4-epoxycyclohexylmethyl methacrylate (trade name: CYCLOMER M100, produced by Daicel Chemical Industries, Ltd.). These may be used either alone respectively or in combinations with each other.
Favorable examples of the (iv) polymerizable unsaturated monomers having the isocyanate group include 2-methacryloyloxyethyl isocyanate (trade name: Karenz MOI, produced by SHOWA DENKO Corporation), methacryloyl isocyanate (trade name: MAI, produced by Nippon Paint Co., Ltd.), and m-isopropenyl-xcex1,xcex1-dimethylbenzyl isocyanate (trade name: m-TMI, produced by Takeda Chemical Industries, Ltd.). These may be used either alone respectively or in combinations with each other.
Favorable examples of the (v) polymerizable unsaturated monomers having the active carbonyl group include acrolein, diacetone(meth)acrylamide, acetoacetoxyethyl (meth)acrylate, formylstyrol, vinyl alkyl ketones having 4 to 7 carbon atoms (e.g. vinyl methyl ketone, vinyl ethyl ketone, vinyl butyl ketone), (meth)acryloxyalkylpropenal, diacetone (meth)acrylate, and acetonyl (meth)acrylate. These may be used either alone respectively or in combinations with each other.
Favorable examples of the (vi) polymerizable unsaturated monomers having the oxazoline group include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-methyl-2-oxazoline, and 2-isopropenyl-5-ethyl-2-oxazoline. These may be used either alone respectively or in combinations with each other.
The aforementioned other polymerizable unsaturated monomer (c), which is copolymerizable with the polymerizable unsaturated monomer (a) and/or the polymerizable unsaturated monomer (b) having a reactive group and is used if necessary, is not especially limited, but favorable specific examples thereof include the following:
(meth)acrylic acid alkyl esters such as methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, sec-butyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, isoamyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isodecyl (meth)acrylate, tridecyl (meth)acrylate, cyclohexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, n-lauryl (meth)acrylate, benzyl (meth)acrylate, dicyclopentanyl (meth)acrylate, n-stearyl (meth)acrylate, isostearyl (meth)acrylate, isobornyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, allyl (meth)acrylate, 2-(acetoacetoxy)ethyl (meth)acrylate, and phenoxyethyl (meth)acrylate;
styrenic monomers such as styrene, xcex1-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-n-butylstyrene, p-t-butylstyrene, p-n-hexylstyrene, p-n-octylstyrene, p-n-nonylstyrene, p-n-dodecylstyrene, and p-phenylstyrene;
vinyl compounds such as vinyltoluene and divinylbenzene;
vinyl esters such as vinyl acetate, vinyl propionate, vinyl chloride, vinylidene chloride, vinyl n-butyrate, vinyl benzoate, vinyl p-t-butylbenzoate, vinyl pivalate, vinyl 2-ethylhexanoate, and vinyl laurate;
(poly)alkylene glycol (meth)acrylates such as methoxydiethylene glycol (meth)acrylate, methoxytetraethylene glycol (meth)acrylate, methoxydipropylene glycol (meth)acrylate, and methoxytetrapropylene glycol (meth)acrylate;
fluorine-containing polymerizable unsaturated monomers such as trifluoroethyl (meth)acrylate, tetrafluoropropyl (meth)acrylate, octafluoropentyl (meth)acrylate, heptadodecafluorodecyl acrylate, xcex2-(perfluorooctyl)ethyl (meth)acrylate, hexafluoropropyl methacrylate, and perfluorooctylethyl (meth)acrylate;
silicon-containing polymerizable unsaturated monomers such as vinyltrichlorosilane, vinyltris(xcex2-methoxyethoxy)silane, vinyltriethoxysilane, vinyltrimethoxysilane, xcex3-methacryloxypropyltrimethoxysilane, and trimethylsiloxyethyl methacrylate;
nitrogen-atom-containing polymerizable unsaturated monomers such as (meth)acrylamide, N,N-dimethylaminopropylacrylamide, N-isopropylacrylamide, t-butylacrylamide, methylenebis(meth)acrylamide, N-methoxymethylacrylamide, N-ethoxymethylacrylamide, N-butoxymethylacrylamide, N-methylol(meth)acrylamide, N,Nxe2x80x2-dimethylaminoethyl (meth)acrylate, N,Nxe2x80x2-diethylaminoethyl (meth)acrylate, N-methyl-N-vinylformamide, dimethylaminoethyl methacrylate sulfate salts, N-vinylpyridine, N-vinylimidazole, N-vinylpyrrol, N-vinylpyrrolidone, diacetoneacrylamide, N-phenylmaleimide, N-cyclohexylmaleimide, and (meth)acrylonitrile;
multifunctional polymerizable unsaturated monomers such as (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, (poly)butylene glycol di(meth)acrylate, EO-modified trimethylolpropane triacrylate, trimethylolpropane triacrylate, pentaerythritol tetraacrylate, and dipentaerythritol hexaacrylate;
vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isopropyl ether, vinyl n-propyl ether, vinyl isobutyl ether, vinyl n-butyl ether, vinyl n-amyl ether, vinyl isoamyl ether, vinyl 2-ethylhexyl ether, vinyl n-octadecyl ether, cyanomethyl vinyl ether, 2,2-dimethylaminoethyl vinyl ether, 2-chloroethyl vinyl ether, xcex2-difluoromethyl vinyl ether, benzyl vinyl ether, phenyl vinyl ether, and divinyl ether;
allyl esters such as allyl acetate and allyl benzoate;
allyl ethers such as allyl ethyl ether, allyl glycidyl ether, and allyl phenylether;
ultraviolet-absorbent polymerizable unsaturated monomers such as 2-[2xe2x80x2-hydroxy-5xe2x80x2-(meth)acryloyloxyethylphenyl]-2H-benzotriazole, 2-[2xe2x80x2-hydroxy-5xe2x80x2-(meth)acryloyloxypropylphenyl]-2H-benzotriazole, 2-[2xe2x80x2-hydroxy-5xe2x80x2-(meth)acryloyloxyhexylphenyl]-2H-benzotriazole, 2-[2xe2x80x2-hydroxy-3xe2x80x2-tert-butyl-5xe2x80x2-(meth)acryloyloxyethylphenyl]-2H-benzotriazole, 2-[2xe2x80x2-hydroxy-3xe2x80x2-tert-butyl-5xe2x80x2-(meth)acryloyloxyethylphenyl]-5-chloro-2H-benzotriazole, 2-[2xe2x80x2-hydroxy-5xe2x80x2-tert-butyl-3xe2x80x2-(meth)acryloyloxyethylphenyl]-2H-benzotriazole, 2-[2xe2x80x2-hydroxy-5xe2x80x2-(meth)acryloyloxyethylphenyl]-5-chloro-2H-benzotriazole, 2-[2xe2x80x2-hydroxy-5xe2x80x2-(meth)acryloyloxyethylphenyl]-5-methoxy-2H-benzotriazole, 2-[2xe2x80x2-hydroxy-5xe2x80x2-(meth)acryloyloxyethylphenyl]-5-cycno-2H-benzotriazole, 2-[2xe2x80x2-hydroxy-5xe2x80x2-(meth)acryloyloxyethylphenyl]-5-t-butyl-2H-benzotriazole, 2-[2xe2x80x2-hydroxy-5xe2x80x2-(xcex2-methacryloyloxyethoxy)-3xe2x80x2-tert-butylphenyl]-4-tert-butyl-2H-benzotriazole, 2-hydroxy-4-methacryloxybenzophenone, 2-hydroxy-4-(2-hydroxy-3-methacryloyloxy)propoxybenzophenone, 2-hydroxy-4-(2-methacryloxy)ethoxybenzophenone, and 2-hydroxy-4-vinyloxycarbonylmethoxybenzophenone; and
ultraviolet-stable polymerizable unsaturated monomers such as 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine, 4-(meth)acryloyloxy-1,2,2,6,6-pentamethylpiperidine, 4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine, 4-(meth)acryloylamino-1,2,2,6,6-pentamethylpiperidine, 4-cyano-4-(meth )acryloylamino-2,2,6,6-tetramethylpiperidine, 4-crotonoyloxy-2,2,6,6-tetramethylpiperidine, 4-crotonoylamino-2,2,6,6-tetramethylpiperidine, 1-(meth)acryloyl-4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine, 1-(meth)acryloyl-4-cyano-4-(meth)acryloylamino-2,2,6,6-tetramethylpiper idine, and 1-crotonoyl-4-crotonoyloxy-2,2,6,6-tetramethylpiperidine. These may be used either alone respectively or in combinations with each other.
If the polymerizable unsaturated monomer (b) having a reactive group, such as (i) to (vi) above, is used, the reactive group can be introduced into the (meth)acrylate ester-based polymer (I). In the case, where the (meth)acrylate ester-based polymer (I) in the present invention has the reactive group, the use thereof jointly with the crosslinking agent having at least two functional groups that are reactable with the reactive group has the advantage of providing enablement for easily crosslinking the (meth)acrylate ester-based polymer (I) to enhance such as weather resistance, water resistance, impact resistance, and processability of the resulting coating film.
The use of the polymerizable unsaturated monomer having the acidic functional group as exemplified by (ii) above from among the polymerizable unsaturated monomers as exemplified as (i) to (vi) above has the advantage of providing enablement for not only introducing the acidic functional group as the reactive group into the (meth)acrylate ester-based polymer (I) but also enhancing such as the adhesion to polar substrates (e.g. metals), the pigment dispersibility, and the solubility or dispersibility into polar solvents (e.g. water) due to this acidic functional group. In addition, the acidic functional group, which has been introduced into the (meth)acrylate ester-based polymer (I) by the polymerizable unsaturated monomer having the acidic functional group as exemplified by (ii) above, is also favorably useful as an internal catalyst for a crosslinking reaction between the crosslinking agent and the (meth)acrylate ester-based polymer (I) as obtained by using the polymerizable unsaturated monomer having the alcoholic hydroxyl group as exemplified by (i) above.
Of the above other polymerizable unsaturated monomers (c), those which are selected from the group consisting of the (meth)acrylic acid alkyl esters, the vinyl compounds, the silicon-containing polymerizable unsaturated monomers, the fluorine-containing polymerizable unsaturated monomers, the ultraviolet-absorbent polymerizable unsaturated monomers, and the ultraviolet-stable polymerizable unsaturated monomers are used favorably for sufficient exhibition of the effects of the resin composition according to the present invention although there is no especial limitation. Particularly favorable are the (meth)acrylic acid alkyl esters and the vinyl compounds.
The amount of each of the above polymerizable unsaturated monomers which are favorably contained in the aforementioned monomer components, in other words; the content of each of the polymerizable unsaturated monomer (a) denoted by the general formula (1), the polymerizable unsaturated monomer (b) having a reactive group, and the other polymerizable unsaturated monomer (c) in the monomer components, is not especially limited, but, in view of the properties of the (meth)acrylate ester-based polymer (I) as obtained by the present invention and further the properties of the finally obtained resin composition, it is as follows: the content of the polymerizable unsaturated monomer (a), denoted by the general formula (1), in the monomer components is as stated above; and the content of the polymerizable unsaturated monomer (b) having a reactive group is favorably in the range of 1.0 to 40.0 weight %, more favorably 3.0 to 40.0 weight %, still more favorably 5.0 to 35.0 weight %, of the monomer components as used; and the content of the other polymerizable unsaturated monomer (c) is favorably in the range of 0 to 94.0 weight %, more favorably 0 to 87.0 weight %, still more favorably 0 to 75.0 weight %, of the monomer components as used.
The polymerization process for obtaining the (meth)acrylate ester-based polymer (I) in the present invention is not especially limited, but favorably usable examples thereof include conventional various processes which utilize such as heat, ultraviolet rays, radiations, electron beams, and radical polymerization initiators, namely, such as solution polymerization processes, emulsion polymerization processes, suspension polymerization processes, bulk polymerization processes, nonaqueous dispersion polymerization processes, and deposition polymerization processes.
In the case where the polymer (I) in the present invention is obtained by using such as the solution polymerization process from among the above polymerization processes, usable solvents (polymerization solvents) are not especially limited, but favorable specific examples thereof include nonreactive solvents such as organic solvents and water wherein examples of the organic solvents include: aromatic solvents (hydrocarbon solvents) such as toluene, xylene, n-hexane, cyclohexane, industrial gasoline, and reformate; ester solvents such as ethyl acetate, butyl acetate, and propylene glycol methyl ether acetate; ketone solvents such as methyl ethyl ketone, ethyl acetoacetate, acetylacetone, diacetone alcohol, methyl isobutyl ketone, methyl amyl ketone, and acetone; aliphatic alcohol solvents such as methanol, ethanol, isopropyl alcohol and n-butanol; alkylene glycol monoalkyl ether solvents such as ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, and propylene glycol monomethyl ether. These may be used either alone respectively or in combinations with each other.
In the case where the polymer (I) in the present invention is obtained by using such as the emulsion polymerization process from among the above polymerization processes, examples of usable emulsifiers include anionic surfactants, cationic surfactants, nonionic surfactants, amphoteric surfactants, high-molecular surfactants, and polymerizable surfactants having at least one polymerizable carbon-carbon unsaturated bond per molecule. These may be used either alone respectively or in combinations with each other.
The aforementioned anionic surfactant is not especially limited, but favorable specific examples thereof include: alkaline-metal alkyl sulfates such as sodium dodecyl sulfate and potassium dodecyl sulfate; ammonium alkyl sulfates such as ammonium dodecyl sulfate; sodium dodecyl polyglycol ether sulfate, sodium sulfocinnoate, and alkaline-metal salts of sulfonated paraffin; alkylsulfonates such as ammonium salts of sulfonated paraffin; fatty acid salts such as sodium laurate; alkylarylsulfonates such as sodium dodecylbenzenesulfonate and alkaline-metal sulfates of alkali phenol hydroxyethylene; higher-alkylnaphthalenesulfonate salts, naphthalenesulfonic acid-formalin condensation products, dialkylsulfosuccinate salts, polyoxyethylene alkyl sulfate salts, and polyoxyethylene alkylaryl sulfate salts.
The aforementioned cationic surfactant is not especially limited, but favorable specific examples thereof include triethanolamine oleate and triethanolamine abietate.
The aforementioned nonionic surfactant is not especially limited, but favorable specific examples thereof include: polyoxyethylene alkyl ethers, polyoxyethylene alkyl aryl ethers, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, and fatty acid monoglycerides such as glycerol monolaurate; poly(oxyethylene-oxypropylene) copolymers, and products formed by condensation of ethylene oxide with fatty acid amines, amides, or acids.
The aforementioned high-molecular surfactant is not especially limited, but favorable specific examples thereof include: poly(vinyl alcohol), poly(sodium (meth)acrylate), poly(potassium (meth)acrylate), poly(ammonium (meth)acrylate), poly(hydroxyethyl (meth)acrylate), poly(hydroxypropyl (meth)acrylate), copolymers of at least two kinds of polymerizable monomers (which are structural units of these polymers) or copolymers of them with other monomers, and phase transfer catalysts such as crown ethers.
The aforementioned polymerizable surfactant is not especially limited, but favorable specific examples thereof include: anionic polymerizable surfactants such as sodium propenyl-2-ethylhexylbenzenesulfosuccinate, sulfate esters of polyoxyethylene (meth)acrylate, ammonium polyoxyethylene alkylpropenyl ether sulfates, and phosphate esters of polyoxyethylene (meth)acrylate; and nonionic polymerizable surfactants such as polyoxyethylene alkylbenzene ether (meth)acrylate and polyoxyethylene alkyl ether (meth)acrylate.
The amount of the aforementioned emulsifier, as used, is not especially limited, but is specifically in the range of favorably 0.1 to 20 weight %, more favorably 0.2 to 10 weight %, still more favorably 0.3 to 6 weight %, relative to the total weight of the monomer component including the polymerizable unsaturated monomer of the general formula (1) as an essential component. In the case where the amount of the aforementioned emulsifier as used is smaller than 0.1 weight % relative to the total weight of the monomer component, there are disadvantages of involving the deterioration of the dispersing stability of the polymer in the resin composition according to the present invention. In the case where the amount of the aforementioned emulsifier is larger than 20 weight %, there are disadvantages of involving the deterioration of such as water resistance of a coating film as formed when the aforementioned resin composition is favorably used for such as paints.
As to the aforementioned emulsion polymerization, the reaction temperature in the step of polymerizing the monomer component is favorably in the range of 10 to 100xc2x0 C., more favorably 40 to 90xc2x0 C.
The organic solvents or water, which are favorably used for the above solution polymerization or emulsion polymerization, are favorably used in such an amount that the weight percentage of the monomer components including such as polymerizable unsaturated monomer (a) of the general formula (1) can be in the range of 5 to 90 weight %, more favorably 10 to 90 weight %, still more favorably 20 to 80 weight %, of the resin composition according to the present invention.
The aforementioned radical polymerization initiator, as used for the above various polymerization processes such as solution polymerization or emulsion polymerization, is not especially limited, but favorable specific examples thereof include: azo initiators such as 2,2xe2x80x2-azobisisobutyronitrile, 2,2xe2x80x2-azobis(2-amidinopropane) dihydrochloride, 4,4xe2x80x2-azobis(4-cyanopentanoic acid), 2,2xe2x80x2-azobis(2-methylbutyronitrile), and 2,2xe2x80x2-azobis(2,4-dimethylvaleronitrile); and peroxide initiators such as persulfate salts (e.g. potassium persulfate), hydrogen peroxide, peracetic acid, benzoyl peroxide, di-t-butyl peroxide, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, t-butylperoxy-2-ethylhexanoate, t-butyl hydroperoxide, lauryl peroxide, and benzoyl peroxide. In addition, on this occasion, it is also favorable to form redox initiators by combining the above peroxide initiators with reducing agents such as sodium hydrogensulfite, L-ascorbic acid, Rongalit, and sodium metabisulfite.
In addition, in the case where a polymerization promotor is used, this polymerization promotor is not especially limited, but favorable examples thereof include various transition metal ions, specifically, such as ferric sulfate, cupric sulfate, ferric chloride, and cupric chloride.
The aforementioned radical polymerization initiator is used in a ratio of favorably 0.01 to 20 weight %, more favorably 0.05 to 10 weight %, still more favorably 0.1 to 10 weight %, to the total weight of the monomer component including the polymerizable unsaturated monomer (a) of the general formula (1) as an essential component. In the case of such a range of the use, excellent results are provided with regard to the yield of the resulting (meth)acrylate ester-based polymer (I) and the economy.
In the case where the above various polymerization processes are used, furthermore, such as a chain transfer agent or adjusting agent is favorably usable for the purpose of adjusting the molecular weight, if necessary.
Although not especially limited, specific examples of the favorably usable chain transfer agent or adjusting agent include: alcohols such as methanol, ethanol, propanol, and butanol; ketones such as acetone, methyl ethyl ketone, cyclohexanone, and acetophenone; aldehydes such as acetoaldehyde, n-butraldehyde, furfural, and benzaldehyde; mercaptans such as dodecylmercaptan, n-dodecylmercaptan, n-octylmercaptan, 2-ethylhexylthioglycolate esters, laurylmercaptan, thioglycolic acid, octyl thioglycolate, thioglycerol, and 2-mercaptoethanol; thiophenol, and xcex1-methylstyrene dimer.
The aforementioned chain transfer agent or adjusting agent is used in a ratio of favorably 0.01 to 10 weight %, more favorably 0.02 to 5 weight %, to the total weight of the monomer component including the polymerizable unsaturated monomer (a) of the general formula (1) as an essential component.
The (meth)acrylate ester-based polymer (I) in the present invention has a number-average molecular weight in the range of favorably 1,000 to 10,000,000, more favorably 1,500 to 5,000,000, still more favorably 2,000 to 5,000,000. In the case where the aforementioned number-average molecular weight deviates from the above ranges, there is an unfavorable possibility that the properties which can be exhibited by the above (meth)acrylate ester-based polymer (I) and further the properties of the finally obtained resin composition according to the present invention might be deteriorated.
The (meth)acrylate ester-based polymer (I) in the present invention has a glass transition temperature Tg (xc2x0 C.) in the range of favorably xe2x88x9230 to 90xc2x0 C., more favorably xe2x88x9220 to 80xc2x0 C., still more favorably xe2x88x9210 to 70xc2x0 C., particularly favorably 10 to 60xc2x0 C. In the case where the aforementioned glass transition temperature Tg deviates from the above ranges, there is an unfavorable possibility that the properties which can be exhibited by the above (meth)acrylate ester-based polymer (I) and further the properties of the finally obtained resin composition according to the present invention might be deteriorated.
((Meth)acrylate Ester-based Resin Composition)
Hereinafter, a detailed explanation is made about specific examples of the composition according to the present invention.
It is favorable that the (meth)acrylate ester-based resin composition according to the present invention comprises a crosslinking agent along with the (meth)acrylate ester-based polymer (I) as essential components wherein the crosslinking agent has at least two functional groups that are reactable with the reactive group of this polymer (I).
The (meth)acrylate ester-based resin composition according to the present invention is enough if it favorably comprises the (meth)acrylate ester-based polymer (I) and the aforementioned crosslinking agent. In particular, the shape or form of the (meth)acrylate ester-based resin composition is not especially limited, but may be liquid, solid, powdery, or in any other form. Furthermore, in the case where the (meth)acrylate ester-based resin composition is liquid, the (meth)acrylate ester-based resin composition may be either what is called a homogeneous resin composition in which the (meth)acrylate ester-based polymer (I) is entirely dissolved in the solvent, or what is called a heterogeneous resin composition in which the (meth)acrylate ester-based polymer (I) is not entirely dissolved but dispersed in the solvent (dispersion medium). However, there is no especial limitation thereto.
Favorable specific examples of processes for obtaining the aforementioned homogeneous resin composition include: a process comprising the steps of synthesizing the (meth)acrylate ester-based polymer (I) by such as emulsion polymerization, suspension polymerization, or bulk polymerization, and then isolating the synthesized (meth)acrylate ester-based polymer (I), and then entirely dissolving the isolated (meth)acrylate ester-based polymer (I) into such as organic solvents to produce a solution type resin composition; and a process comprising the steps of synthesizing the (meth)acrylate ester-based polymer (I) by solution polymerization, and then, if necessary, newly adding another component to the resultant solution type or pasty resin composition to produce a solution type resin composition. However, there is no especial limitation thereto.
Favorable specific examples of processes for obtaining the aforementioned heterogeneous resin composition include: a process comprising the steps of synthesizing the (meth)acrylate ester-based polymer (I) by such as solution polymerization, bulk polymerization, or deposition polymerization, and then isolating the synthesized (meth)acrylate ester-based polymer (I), and then post-dispersing the isolated (meth)acrylate ester-based polymer (I) into a dispersion medium to produce a resin composition as a dispersion; and a process comprising the steps of synthesizing the (meth)acrylate ester-based polymer (I) by emulsion polymerization, suspension polymerization, or nonaqueous dispersion polymerization, and then, if necessary, newly adding another component to the resultant resin composition standing in a state of a dispersion to produce a resin composition standing in a state of a dispersion. However, there is no especial limitation thereto.
The content of the (meth)acrylate ester-based polymer (I) in the (meth)acrylate ester-based resin composition according to the present invention is favorably in the range of 5 to 90 weight %, more favorably 20 to 85 weight %, particularly favorably 50 to 80 weight %, of the (meth)acrylate ester-based resin composition. In the case where the content of the (meth)acrylate ester-based polymer (I) deviates from the above ranges, there is an unfavorable possibility that the resin composition according to the present invention could not sufficiently exhibit its various properties.
The content of the crosslinking agent in the (meth)acrylate ester-based resin composition according to the present invention is favorably in the range of 1.0 to 40.0 weight %, more favorably 5.0 to 40.0 weight %, of the (meth)acrylate ester-based resin composition. In the case where the content of the crosslinking agent deviates from the above ranges, there is an unfavorable possibility that the resin composition according to the present invention could not sufficiently exhibit its various properties.
The (meth)acrylate ester-based polymer (I), which is contained as an essential component in the (meth)acrylate ester-based resin composition according to the present invention, favorably has a reactive. group. This reactive group is not especially limited, but, as is mentioned above, favorable examples thereof include an alcoholic hydroxyl group, an acidic functional group, an epoxy group, an active carbonyl group, an oxazoline group, and an isocyanate group.
Similarly, the aforementioned crosslinking agent, which is contained as an essential component in the (meth)acrylate ester-based resin composition according to the present invention, is a compound having at least two functional groups that are reactable with the reactive group of the aforementioned polymer (I), and crosslinking agents which are favorable for the polymers having the above reactive groups can be exemplified as follows.
Acrylic Polyol
The (meth)acrylate ester-based polymer (I) is, for example, an acrylic polyol which is obtained by a process including the step of polymerizing monomer components including the polymerizable unsaturated monomer (a) and an alcoholic-hydroxyl-group-containing polymerizable unsaturated monomer as essential components.
Favorably usable as the aforementioned alcoholic-hydroxyl-group-containing polymerizable unsaturated monomer is at least one of those which are exemplified by (i) above of the polymerizable unsaturated monomers (b) having reactive groups.
In this case, favorable examples of the crosslinking agent include polyisocyanate compounds, blocked isocyanate compounds, and aminoplast resins, and at least one of them is favorably usable. These may be used either alone respectively or in combinations with each other.
Favorable examples of the polyisocyanate compounds as the aforementioned crosslinking agent include aliphatic, alicyclic, or aromatic polyisocyanate compounds such as trimethylene diisocyanate, 1,6-hexamethylene diisocyanate, (hydrogenated) tolylene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, and (hydrogenated) xylylene diisocyanate. These may be used either alone respectively or in combinations with each other.
Favorable examples of the blocked isocyanate compounds as the aforementioned crosslinking agent include compounds obtained by causing such as caprolactones (e.g. caprolactams), phenols (e.g. phenol), alcohols (e.g. tertiary alcohols), and oximes to react at terminals of the above polyisocyanate compounds.
Favorable examples of the aminoplast resins as the aforementioned crosslinking agent include methyl-etherated melamine resins, butyl-etherated melamine resins, hexamethoxymelamine resins, butyl-etherated benzoguanamine resins, butyl-etherated cyclohexylbenzoguanamine resins, and water-solubilized products of these resins. These may be used either alone respectively or in combinations with each other.
Acidic-functional-group-containing Resin
The (meth)acrylate ester-based polymer (I) is, for example, an acidic-functional-group-containing resin which is obtained by a process including the step of polymerizing monomer components including the polymerizable unsaturated monomer (a) and an acidic-functional-group-containing polymerizable unsaturated monomer as essential components.
In the case where the reactive group is an acidic functional group such as a carboxyl group, sulfonic acid group, or phosphoric acid group, favorably usable as the aforementioned acidic-functional-group-containing monomer is at least one of the acidic-functional-group-containing polymerizable unsaturated monomers which are exemplified by (ii) above of the polymerizable unsaturated monomers (b) having reactive groups.
In this case, favorable examples of the crosslinking agent include epoxy-group-containing compounds, metal chelate compounds, polyisocyanate compounds, oxazoline-group-containing compounds, and carbodiimide-group-containing compounds, and at least one of them is favorably usable.
Favorable examples of the epoxy-group-containing compounds as the aforementioned crosslinking agent include bisphenol A type epoxy resins, bisphenol F type epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins, glycidylamine type epoxy resins, alicyclic epoxy compounds, and hydrogenated bisphenol A type epoxy resins. These may be used either alone respectively or in combinations with each other. Of them, particularly, the alicyclic epoxy compounds and the hydrogenated bisphenol A type epoxy resins are favorable.
Favorable examples of the metal chelate compounds as the aforementioned crosslinking agent include: aluminum chelates such as aluminum tris(acetylacetonate); acetylacetone compounds of such as titanium, zirconium, copper, cobalt, and zinc; and ammonia-coordinated compounds such as polyamines. These may be used either alone respectively or in combinations with each other.
Favorably usable examples of the polyisocyanate compounds as the aforementioned crosslinking agent include the same as those of the aforementioned xe2x80x9cpolyisocyanate compounds as the crosslinking agent in the explanation about the acrylic polyolxe2x80x9d. These may be used either alone respectively or in combinations with each other.
Favorable examples of the oxazoline-group-containing compounds as the aforementioned crosslinking agent include 2,2xe2x80x2-bis(2-oxazoline), 2,2xe2x80x2-methylene-bis(2-oxazoline), 2,2xe2x80x2-ethylene-bis(2-oxazoline), 2,2xe2x80x2-trimethylene-bis(2-oxazoline), 2,2xe2x80x2-tetramethylene-bis(2-oxazoline), 2,2xe2x80x2-hexamethylene-bis(2-oxazoline), 2,2xe2x80x2-octamethylene-bis(2-oxazoline), 2,2xe2x80x2-ethylene-bis(4,4xe2x80x2-dimethyl-2-oxazoline), 2,2xe2x80x2-p-phenylene-bis(2-oxazoline), 2,2xe2x80x2-m-phenylene-bis(4,4xe2x80x2-dimethyl-2-oxazoline), bis(2-oxazolinylcyclohexane) sulfide, and bis(2-oxazolinylnorbornane) sulfide. These may be used either alone respectively or in combinations with each other.
Favorable examples of the carbodiimide-group-containing compounds as the aforementioned crosslinking agent include Carbodirite V-02, V-04, V-06, E-01, and E-02 (produced by Nisshin Boseki Co., Ltd.). These may be used either alone respectively or in combinations with each other.
Epoxy-group-containing Resin
The (meth)acrylate ester-based polymer (I) is, for example, an epoxy-group-containing resin which is obtained by a process including the step of polymerizing monomer components including the polymerizable unsaturated monomer (a) and an epoxy-group-containing polymerizable unsaturated monomer as essential components.
Favorably usable as the aforementioned epoxy-group-containing monomer is at least one of the polymerizable unsaturated monomers which are exemplified by (iii) above of the polymerizable unsaturated monomers (b) having reactive groups.
In this case, favorable examples of the crosslinking agent include carboxyl-group-containing compounds, thiol-group-containing compounds, and polyamine compounds, and at least one of them is favorably usable.
Favorable examples of the carboxyl-group-containing compounds as the aforementioned crosslinking agent include: carboxyl-group-containing polyesters obtained by condensation polymerization of unsaturated polybasic acids (represented by such as maleic anhydride, fumaric acid, citraconic acid, and itaconic acid) or saturated polybasic acids (represented by such as phthalic anhydride, isophthalic acid, terephthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, and succinic acid) with polyhydric alcohol components (represented by such as ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol glycol, diethylene glycol, triethylene glycol, 1,4-cyclohexanedimethanol, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol); and polycarboxylic acids. Of them, particularly, the polycarboxylic acids are favorable.
Favorable examples of the polycarboxylic acids include: aliphatic dibasic acids (e.g. adipic acid, sebacic acid, azelaic acid, decanedicarboxylic acid, hexadecanedicarboxylic acid, eicosanedicarboxylic acid, tetraeicosanedicarboxylic acid, maleic acid, citraconic acid, itaconic acid, glutaric acid, suberic acid, pimelic acid, eicosanedioic acid, dodecanedioic acid) or their ester compounds and acid anhydrides; aromatic polycarboxylic acids (e.g. isophthalic acid, phthalic acid, trimellitic acid, piperic acid, pyromellitic acid) or their ester compounds and acid anhydrides; alicyclic dibasic acids (e.g. hexahydrophthalic acid, hexahydroisophthalic acid, methylhexahydrophthalic acid, tetrahydrophthalic acid) or their ester compounds and acid anhydrides; polybasic acids (e.g. citric acid, butanetetracarboxylic acid) and those which have at least two carboxyl groups per molecule among the polymerizable unsaturated monomers which are exemplified by (ii) above, or their ester compounds and acid anhydrides. These may be used either alone respectively or in combinations with each other.
Favorable examples of the thiol-group-containing compounds as the aforementioned crosslinking agent include triazinethiols. These may be used either alone respectively or in combinations with each other.
Favorable examples of the polyamine compounds as the aforementioned crosslinking agent include: linear aliphatic polyamines such as diethylenetriamine (DETA), triethylenetetramine (TETA), and polyoxypropylenetriamine; and cyclic amines such as menthenediamine, isophoronediamine, diaminodicyclohexylmethane, and bis(aminomethyl)cyclohexane. These may be used either alone respectively or in combinations with each other.
Active-carbonyl-group-containing Resin
The (meth)acrylate ester-based polymer (I) is, for example, an active-carbonyl-group-containing resin which is obtained by a process including the step of polymerizing monomer components including the polymerizable unsaturated monomer (a) and an active-carbonyl-group-containing polymerizable unsaturated monomer as essential components.
Favorably usable as the aforementioned active-carbonyl-group-containing polymerizable unsaturated monomer is at least one of the polymerizable unsaturated monomers which are exemplified by (v) above of the polymerizable unsaturated monomers (b) having reactive groups.
In this case, favorable examples of the crosslinking agent include hydrazino-group-containing compounds, and at least one of them is favorably usable.
Favorable examples of the hydrazino-group-containing compounds as the aforementioned crosslinking agent include dicarboxylic hydrazides having, for example, 2 to 10, particularly, 4 to 6 carbon atoms (e.g. oxalic dihydrazide, malonic dihydrazide, succinic dihydrazide, glutaric dihydrazide, adipic dihydrazide, sebacic dihydrazide, maleic dihydrazide, fumaric dihydrazide, itaconic dihydrazide) and aliphatic water-soluble dihydrazines having 2 to 4 carbon atoms (e.g. ethylene-1,2-dihydrazine, propylene-1,3-dihydrazine, butylene-1,4-dihydrazine). These may be used either alone respectively or in combinations with each other.
Oxazoline-group-containing Resin
The (meth)acrylate ester-based polymer (I) is, for example, an oxazoline-group-containing resin which is obtained by a process including the step of polymerizing monomer components including the polymerizable unsaturated monomer (a) and an oxazoline-group-containing polymerizable unsaturated monomer as essential components.
Favorably usable as the aforementioned oxazoline-group-containing polymerizable unsaturated monomer is at least one of the polymerizable unsaturated monomers which are exemplified by (vi) above of the polymerizable unsaturated monomers (b) having reactive groups.
In this case, favorable examples of the crosslinking agent include carboxyl-group-containing compounds, epoxy-group-containing compounds, and thiol-group-containing compounds, and at least one of them is favorably usable.
Favorably usable examples of the carboxyl-group-containing compounds as the aforementioned crosslinking agent include the same as those of the aforementioned xe2x80x9ccarboxyl-group-containing compounds as the crosslinking agent in the explanation about the epoxy-group-containing resinxe2x80x9d. These may be used either alone respectively or in combinations with each other.
Favorably usable examples of the epoxy-group-containing compounds as the aforementioned crosslinking agent include the same as those of the aforementioned xe2x80x9cepoxy-group-containing compounds as the crosslinking agent in the explanation about the acidic-functional-group-containing resinxe2x80x9d. These may be used either alone respectively or in combinations with each other.
Favorable examples of the thiol-group-containing compounds as the aforementioned crosslinking agent include triazinethiols. These may be used either alone respectively or in combinations with each other.
Isocyanate-group-containing Resin
The (meth)acrylate ester-based polymer (I) is, for example, an isocyanate-group-containing resin which is obtained by a process including the step of polymerizing monomer components including the polymerizable unsaturated monomer (a) and an isocyanate-group-containing polymerizable unsaturated monomer as essential components.
Favorably usable as the aforementioned isocyanate-group-containing polymerizable unsaturated monomer is at least one of the polymerizable unsaturated monomers which are exemplified by (iv) above of the polymerizable unsaturated monomers (b) having reactive groups.
In this case, favorable examples of the crosslinking agent include hydroxyl-group-containing compounds and amino-group-containing compounds, and at least one of them is favorably usable.
Favorable examples of the hydroxyl-group-containing compounds as the aforementioned crosslinking agent include combined resins such as acrylic polyol resins, polyester resins, polyether resins (e.g. polyethylene ethers, polypropylene ethers), epoxy resins, urethane resins, and acrylic urethane resins. These may be used either alone respectively or in combinations with each other.
Favorable examples of the amino-group-containing compounds as the aforementioned crosslinking agent include the same compounds as specific examples which are enumerated as the aforementioned xe2x80x9cpolyamine compounds as the crosslinking agentxe2x80x9d. These may be used either alone respectively or in combinations with each other.
In the case where the form of the (meth)acrylate ester-based resin composition according to the present invention is a liquid, an organic solvent and/or water is favorably used as the solvent or dispersion medium which is contained as a component in the aforementioned resin composition. Although there is no especial limitation, specific examples thereof include organic solvents and water wherein examples of the organic solvents include: aromatic solvents such as toluene, xylene, industrial gasoline, and reformate; ester solvents such as ethyl acetate, butyl acetate, and propylene glycol methyl ether acetate; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, and methyl amyl ketone; aliphatic alcohol solvents such as isopropyl alcohol and n-butanol; alkylene glycol monoalkyl ether solvents such as ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, and propylene glycol monomethyl ether. One or two or more of them are favorably usable.
In the case where the form of the (meth)acrylate ester-based resin composition according to the present invention is a liquid, the content of the aforementioned solvent or dispersion medium in the aforementioned resin composition is favorably in the range of 10 to 94 weight %, more favorably 15 to 80 weight %, particularly favorably 20 to 70 weight %, of the (meth)acrylate ester-based resin composition. In the case where this content deviates from the above ranges, there is an unfavorable possibility that the resin composition according to the present invention could not sufficiently exhibit its various properties.
In the case where the form of the (meth)acrylate ester-based resin composition according to the present invention is a liquid, particularly, a dispersion, this resin composition may further comprise a compound having dispersibility or emulsifiability. Favorably usable examples of the compound having dispersibility or emulsifiability include polymers having dispersibility or emulsifiability in addition to so-called dispersants and emulsifiers.
Favorably usable examples of the aforementioned dispersants and emulsifiers include those which are aforementioned as emulsifiers that can be used for emulsion polymerization, namely, anionic surfactants, cationic surfactants, nonionic surfactants, amphoteric surfactants, high-molecular surfactants, and polymerizable surfactants having at least one polymerizable carbon-carbon unsaturated bond per molecule.
The aforementioned polymers having dispersibility or emulsifiability are not especially limited, but favorable specific examples thereof include (partially saponified or) carboxyl-group-modified poly(vinyl alcohol), methyl cellulose, hydroxyethyl cellulose, poly(vinylpyrrolidone), polycarboxylic acid-based high-molecular emulsifiers, EO/PO block polymers, poly(vinyl alcohol), poly(sodium (meth)acrylate), poly(potassium (meth)acrylate), poly(ammonium (meth)acrylate), poly(hydroxyethyl (meth)acrylate), poly(hydroxypropyl (meth)acrylate), copolymers of at least two kinds of polymerizable monomers (which are structural units of these polymers) or copolymers of them with other monomers, and phase transfer catalysts such as crown ethers. These may be used either alone respectively or in combinations with each other.
If necessary, fitly, the (meth)acrylate ester-based resin composition according to the present invention may favorably further comprise various paint additives such as pigments, aggregates, fillers, curing catalysts, modifying agents, leveling agents, dispersants, plasticizers, stabilizers, antioxidants, pinhole inhibitors, ultraviolet absorbents as added, ultraviolet stabilizers as added, and dyes (wherein the additives are not limited thereto). These may be used either alone respectively or in combinations with each other.
As is mentioned above, the (meth)acrylate ester-based resin composition according to the present invention can favorably further comprise the pigment and the aggregate.
The aforementioned pigment is not especially limited in kind, but favorable specific examples thereof include: inorganic pigments such as white pigments (e.g. titanium oxide, antimony trioxide; zinc white, lithopone, white lead) and color pigments (e.g. carbon black, chrome yellow, molybdate orange, red iron oxide); and organic pigments such as azo compounds (e.g. benzidine, Hansa yellow) and phthalocyanines (e.g. phthalocyanine blue). These may be used either alone respectively or in combinations with each other.
In the case where the (meth)acrylate ester-based resin composition according to the present invention is, for example, used as paints, pigments of which the weather resistance is so good as not to deteriorate the weather resistance of the resulting paint film are desirably selected from among the aforementioned pigments. For example, as to the titanium oxide which is a white pigment, the use of rutile type titanium oxide is preferable to the use of anatase type titanium oxide in respect to the weather resistance of the resulting paint film. In addition, as to the rutile type titanium oxide, chlorine process titanium oxide is preferable to sulfuric acid process titanium oxide in respect to being able to prolong the period of time of retaining and exhibiting the weather resistance.
As to the aforementioned aggregate, its kind may be either a transparent aggregate or a color aggregate. Although not especially limited, favorable specific examples of the transparent aggregate include feldspar, silica sand, silica stone, crystalline lime stone sand, glass beads, and synthetic resin beads, and favorable specific examples of the color aggregate include marble powder, granite powder, serpetinite, fluorite, color silica sand powder, and color pottery powder. These may be used either alone respectively or in combinations with each other.
In the case where the (meth)acrylate ester-based resin composition according to the present invention contains the aforementioned additives such as pigments, aggregates, and fillers, the content of these additives in the resin composition is favorably less than 40 weight % for uses for such as clear paints, and further is favorably in the range of 5 to 80 weight %, more favorably 10 to 70 weight %, still more favorably 20 to 60 weight %, for uses for such as enamel paints, in order for the additives to sufficiently exhibit their effects.
As is mentioned above, the (meth)acrylate ester-based resin composition according to the present invention can favorably further comprise the curing catalyst. This case has the advantage in that it is possible to promote a crosslinking reaction between the (meth)acrylate ester-based polymer (I) and the crosslinking agent which are essential components of the(meth)acrylate ester-based resin composition according to the present invention.
The aforementioned curing catalyst is not especially limited, but favorable specific examples thereof include: organic sulfonic acid compounds such as dodecylbenzenesulfonic acid, p-toluenesulfonic acid, 1-naphthalenesulfonic acid, and 2-naphthalenesulfonic acid; mixtures or reaction products of the aforementioned organic sulfonic acid compounds with nitrogen-atom-containing compounds (e.g. 1-amino-2-propanol, monoethanolamine, diethanolamine, 2-(methylamino)ethanol, 2-dimethylmethanolamine, 2-amino-2-methyl-1-propanol, diisopropanolamine, 3-aminopropanol, 2-methylamino-2-methylpropanol, morpholine, oxazolidine, 4,4-dimethyloxazolidine, 3,4,4-trimethyloxazolidine); phosphoric acid or phosphate esters, such as phosphoric acid, monomethyl phosphate, monoethyl phosphate, monobutyl phosphate, monooctyl phosphate, monododecyl phosphate, dimethyl phosphate, diethyl phosphate, dibutyl phosphate, dioctyl phosphate, and didodecyl phosphate; addition reaction products of epoxy compounds (e.g. propylene oxide, butylene oxide, cyclohexene oxide, glycidyl methacrylate, glycidol, acryl glycidyl ether, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyltrimethyldimethoxysilane, CARDURA E produced by Yuka Shell Epoxy Co., Ltd., Epikote 828 produced by Yuka Shell Epoxy Co., Ltd., Epikote 1001 produced by Yuka Shell Epoxy Co., Ltd.) with phosphoric acid and/or monophosphate esters; amines such as hexylamine, di-2-ethylhexylamine, N,N-dimethyldodecylamine, DABCO, DBU, morpholine, and diisopropanolamine; reaction products of these amines with acidic phosphate esters; alkaline compounds such as sodium hydroxide and potassium hydroxide; quaternary ammonium salts such as benzyltriethylammonium chloride or bromide and tetrabutylammonium chloride or bromide; phosphonium salts; divalent tin compounds such as tin octylate and tin stearate; tetravalent organotin compounds such as dibutyltin compounds (e.g. dibutyltin dioctoate, dibutyltin dilaurate, dibutyltin diacetate, dibutyltin diacetylacetonate, dibutyltin bistriethoxysilicate, dibutyltin distearate, dibutyltin maleate) and dioctyltin compounds (e.g. dioctyltin dilaurate, dioctyltin distearate, dioctyltin maleate); organotitanate compounds such as tetramethoxytitanium and tetrastearyloxytitanium; organoaluminum compounds such as aluminum isopropoxide and aluminum acetylacetonate; and organozirconium compounds such as zirconia stearate and zirconium tetraacetylacetonate. These may be used either alone respectively or in combinations with each other.
As is mentioned above, the (meth)acrylate ester-based resin composition according to the present invention can favorably further comprise the modifying agent, fitly if necessary.
The aforementioned modifying agent is not especially limited, but favorable specific examples thereof include polystyrene resins, polyethylene resins, polypropylene resins, polyurethane resins, polyester resins, poly(vinyl alcohol) resins, acrylonitrile-butadiene-styrene resins, fluororesins, epoxy resins, alkyd resins, silicone resins, vinyl acetate resins, polyester-modified acrylic resins, condensed products of organosilicates, and polyether resins. These may be used either alone respectively or in combinations with each other.
In the case where the (meth)acrylate ester-based resin composition according to the present invention is cured, curing conditions (crosslinking reaction conditions) are not especially limited, and usually the resin composition may be cured at normal temperature or under heating, but specifically the curing temperature is, for example, in the, range of xe2x88x9220 to 300xc2x0 C., favorably 0 to 250xc2x0 C. In the case where the curing temperature is lower than xe2x88x9220xc2x0 C., curing is so bad that the properties might not be exhibited. In the case where the curing temperature is higher than 300xc2x0 C., organic chains decompose, so the properties might not be exhibited.
In addition, in the case where the (meth)acrylate ester-based resin composition according to the present invention is cured, it is allowed to use usually commonly known curing methods, of which the specific examples include: methods in which curing is carried out by irradiating ultraviolet rays or electron beams; methods in which curing is carried out by oxidation; and moisture curing methods. These may be used jointly with the above curing method by drying.
As is mentioned above, the (meth)acrylate ester-based resin composition according to the present invention comprises the (meth)acrylate ester-based polymer and the crosslinking agent, and this resin composition may be such that these various components can be mixed together when the resin composition is used. For example, the resin composition may be either a two-liquid type such that the components are mixed together just before the resin composition is used, or a one-liquid type such that the components are beforehand mixed together, and there is no especial limitation. However, for example, in the case where the components are mixed together at normal temperature, if the combination of the above polymer and the crosslinking agent causes unstableness as the reaction system, the mixing as the two-liquid type is considered preferable to that as the one-liquid type. Therefore, the mode to mix various components of the resin composition according to the present invention may fitly be judged while considering such as combination of the above polymer and the. crosslinking agent.
The above mode to mix various components is not especially limited, but, in the case where the (meth)acrylate ester-based resin composition according to the present invention is used as a solution type resin composition, examples of the above mixing mode include: 1) a mode in which both the above polymer and the crosslinking agent are simultaneously dissolved or dispersed into an identical solvent and thereby mixed together; 2) a mode in which the above polymer and the crosslinking agent are dissolved or dispersed into different solvents, and then both are mixed together; and 3) a mode in which either one of the above polymer and the crosslinking agent is dissolved or dispersed into a solvent and then mixed with the other. In addition, likewise, in the case where the resin composition is used as a powdery resin composition, this resin composition is powdered so as not to contain such as solvent, and examples of the mixing mode therefor include: 1) a mode in which the above polymer and the crosslinking agent are beforehand mixed together by such as melt-kneading or dissolution into a solvent, and the resultant mixture is powdered by pulverization or spraying; and 2) a mode in which the above polymer and the crosslinking agent are powdered separately from each other and then mixed together. The mixing mode is not especially limited, but a favorable mixing mode may be considered fitly according to in what property and state the resin composition according to the present invention is used.
(Uses)
The (meth)acrylate ester-based resin composition according to the present invention favorably has various excellent properties as a resin composition having a crosslinking type curability, and is more favorably excellent particularly in various properties such as weather resistance, heat resistance, water resistance, acid resistance, alkali resistance, warm water resistance, impact resistance, processability, flexibility, hardness, elongation, transparency, luster, fleshy property, mirroring property, pigment dispersibility, and driability. Therefore, although not especially limited, favorable examples of the purpose of using the aforementioned resin composition include the wide range of various uses such as coating agents (e.g. for films, plastics, glass, paper, fibers, leather), pressure sensitive adhesives, and adhesives in addition to various paints such as paints for building exteriors, paints for building materials, paints for metals, paints for plastics, heavy anticorrosive paints, and waterproof paints for roofs.
As is mentioned above, the (meth)acrylate ester-based resin composition according to the present invention may be a solution, solid, powder, or in any other form, and its form may be selected fitly for desired uses. Particularly in the case where the resin composition is prepared as a powdery resin composition, this resin composition is usable as a resin composition for powdery paints, in other words, as a powdery paint.
Similarly to conventional powdery paints, the above powdery paint is not especially limited, but is, for specific example, favorably usable for: surfaces of materials such as glass and heat-resistant plastics; surfaces of metallic materials such as steel, aluminum, zinc, tin, copper, and melt-galvanized steel; surfaces of materials obtained by subjecting these metallic materials to surface treatments such as zinc-phosphating; and surfaces of materials as subjected to coating treatments with such as primers (e.g. by electrodeposition paints), intermediate paints, and undercoat base paints. More specifically, the above powdery paint is favorably usable for the same uses as those of conventional powdery paints, such as automobiles, car parts, electrical home use products, electrical appliances, steel-made furniture, office supplies, plastic articles, building materials, and building exteriors, without especial limitation. Particularly, the above powdery paint is favorably usable for outer and inner plates of cars to which the smoothness of paint films is demanded.
Hereinafter, an explanation is made about the case where the (meth)acrylate ester-based resin composition according to the present invention is used as a powdery paint (a resin composition for powdery paints). As long as there is no especial limitation, the powdery paint as hereinafter referred to is that in the case where the resin composition according to the present invention is used as a powdery paint.
In the case where the powdery paint is coated onto surfaces of the above materials, an arrangement is usually made so that the thickness of the resultant paint film may be in the range of favorably 20 to 200 xcexcm, more favorably 20 to 150 xcexcm, after baking.
The method for coating the powdery paint is not especially limited, but favorable specific examples thereof include methods such as electrostatic spray coating, friction electrification spray coating, and flowing immersion coating.
The above baking is carried out for the purpose of forming a cured paint film after coating the powdery paint. The baking temperature is usually in the range of favorably 120 to 300xc2x0 C., more favorably 120 to 200xc2x0 C., still more favorably 140 to 200xc2x0 C. In addition, the baking period of time is usually in the range of favorably 10 to 60 minutes, more favorably 10 to 50 minutes, at the above temperature.
The mixing ratio between the polymer (I) and the crosslinking agent, which are contained in the powdery paint, is set so that the equivalent ratio between the functional group in the polymer (I) and that in the crosslinking agent may be favorably in the range of xc2xd to {fraction (2/1)}, more favorably in the range of ⅔ to {fraction (3/2)}. In the case where the above mixing ratio is less than xc2xd, inferior results might be provided with regard to such as the storage stability of the paint or the finished external appearance of the resulting paint film. In the case where the above mixing ratio is more than {fraction (2/1)}, sufficient crosslinking density might not be obtained, therefore inferior results might be provided with regard to such as weather resistance, acid resistance, and scratch resistance.
The glass transition temperature Tg (xc2x0 C.) of the polymer (I), which is contained in the powdery paint, is favorably not lower than 40xc2x0 C., more favorably not lower than 45xc2x0 C., in view of blocking resistance as a powdery paint, and favorably not higher than 90xc2x0 C., more favorably not higher than 80xc2x0 C., in view of external appearance of the resulting paint film. Incidentally, the above glass transition temperature Tg is a numerical value which is given by converting a temperature (K), as calculated by Fox""s equation below, into (xc2x0 C.).
1/Tg=xcexa3(Wi/Tgi)
wherein: Wi is a mass distribution of monomer i; and Tgi is Tg of a homopolymer of the monomer i.
The number-average molecular weight (Mn) of the polymer (I), which is contained in the powdery paint, is favorably not lower than 2,000, more favorably not lower than 3,000, in view of blocking resistance and corrosion resistance, and favorably not higher than 20,000, more favorably not higher than 10,000, in view of external appearance of the resulting paint film.
As to the powdery paint, the process for powdering the resin composition is not especially limited, but favorable examples thereof include: i) a process in which the components which are used as the ingredients of the resin composition according to the present invention are premixed, and then the resultant premixture is melt-kneaded and then pulverized and then classified; ii) a process in which the components which are used as the ingredients of the resin composition according to the present invention are beforehand mixed in a solution state like the solvent type paint, and then the resultant mixture is powdered into fine particles by methods such as spray drying. In the process i), the pulverization step favorably goes by multistep in which coarse pulverization is carried out, and then fine pulverization is newly carried out. In addition, the powdered resin compositions as obtained by the processes i) and ii) has a volume-average particle diameter in the range of favorably 5 to 40 xcexcm, more favorably 10 to 25 xcexcm. In the case where the above volume-average particle diameter is smaller than 5 xcexcm, the efficiency of coating by electrostatic coating might be bad. In the case where the above volume-average particle diameter is larger than 40 xcexcm, the smoothness might be bad.
The polymer (I), as contained in the powdery paint, favorably has an epoxy group or hydroxyl group as the reactive group.
For making the above polymer (I) have the epoxy group as the reactive group, it is favorable to use the above (iii) polymerizable unsaturated monomer having the epoxy group as the polymerizable unsaturated monomer (b) and, particularly, glycidyl (meth)acrylate is more favorable. In addition, as to the crosslinking agent used in this case, it is favorable to use the carboxyl-group-containing compound which is mentioned above as what is favorably combined with the epoxy-group-containing resin. In this way, if the combination of the polymer (I) with the crosslinking agent is that of the polymer (I) having the epoxy group with the carboxyl-group-containing compound, then excellent properties such as corrosion resistance, weather resistance, and hardness can be afforded to the resulting paint film to obtain good external appearance of the paint film.
In the case where the above polymer (I) has the epoxy group as the reactive group, the content of the above (iii) polymerizable unsaturated monomer having the epoxy group in the monomer components for obtaining the polymer (I) is favorably in the range of 20 to 70 weight %, more favorably 25 to 45 weight %, of the monomer components. If the above content is not less than 20 weight %, the corrosion resistance and the hardness of the resulting paint film greatly increase. If the above content is not more than 70 weight %, the storage stability of the powdery paint and the external appearance of the resulting paint film are good.
For making the above polymer (I) have the hydroxyl group as the reactive group, it is favorable to use the above (i) polymerizable unsaturated monomer having the alcoholic hydroxyl group as the polymerizable unsaturated monomer (b) and, particularly, 2-hydroxyethyl methacrylate (HEMA) is more favorable. In addition, as to the crosslinking agent used in this case, it is favorable to use the blocked isocyanate compound which is mentioned above as what is favorably combined with the acrylic polyol. In this way, if the combination of the polymer (I) with the crosslinking agent is that of the polymer (I) having the hydroxyl group with the blocked isocyanate compound, then excellent properties such as impact resistance, weather resistance, and hardness can be afforded to the resulting paint film to obtain good external appearance of the paint film.
In the case where the above polymer (I) has the hydroxyl group as the reactive group, the content of the above (i) polymerizable unsaturated monomer having the alcoholic hydroxyl group in the monomer components for obtaining the polymer (I) is favorably in the range of 10 to 65 weight %, more favorably 15 to 40 weight %, of the monomer components. If the above content is not less than 10 weight %, the corrosion resistance and the hardness of the resulting paint film greatly increase. If the above content is not more than 65 weight %, the storage stability of the powdery paint and the external appearance of the resulting paint film are good.
The polymer (I), as contained in the powdery paint, is favorably a product obtained by a process including the step of polymerizing monomer components including the (meth)acrylic acid alkyl ester and the styrenic monomer (among the above polymerizable unsaturated monomers (c)) as essential components. In the case where the (meth)acrylic acid alkyl ester is included in the monomer components, there are advantages in that excellent external appearance or weather resistance can be afforded to the resulting paint film. In the case where the (meth)acrylic acid alkyl ester is used, the content thereof in the monomer components is favorably in the range of 5 to 70 weight %, more favorably 10 to 60 weight %, of the entirety of the monomer components. The above (meth)acrylic acid alkyl ester is not especially limited, but more favorable of those which are enumerated above are methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, i-butyl (meth)acrylate, t-butyl (meth)acrylate, n-propyl (meth)acrylate, i-propyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate, and isobornyl (meth)acrylate.
Hereinafter, an explanation is made about a process for forming a paint film for cars in the case where the resin composition according to the present invention which is a powdery paint is used for forming a paint film for cars.
Favorable as the above process for forming a paint film for cars is also a forming process in either manner of a 1-coat manner in which a colored powdery paint is coated onto a coated product obtained by coating a substrate with an undercoat base paint and, if necessary, an intermediate paint; and a 2-coat manner in which a powdery paint is coated onto a surface of a film of a colored base coat paint. However, a forming process in a 2-coat-and-1-bake (2C1B) manner is particularly favorable for sufficient exhibition of the effects in the case where the resin composition according to the present invention is used as a powdery paint. Incidentally, in the 2-coat-and-1-bake (2C1B) manner, a color metallic paint or an aqueous color interference pattern paint is coated as an aqueous color base paint, and then, while the surface of the resultant paint film has not yet been cured, this surface of the paint film is coated with the powdery paint, and then both the powdery paint and the aqueous color base paint are simultaneously cured by heating.
As to the above 2C1B, specifically, there is the following mode for execution. In this mode, first, a metal- or plastic-made material (to be coated) (e.g. car body) is coated with the aqueous color base paint (having a solid content adjusted into the range of 10 to 60 weight %) by spray coating such as airless spray, air spray, or electrostatic coating (directly or after being coated with an undercoat base paint (e.g. cationic electrodeposition paint) and, if necessary, an intermediate paint and then cured) so that the thickness of a cured film of the aqueous color base paint will be in the range of 10 to 60 xcexcm, favorably 10 to 40 xcexcm. After the coating has been completed, the coated material is left alone at room temperature for about 1 to about 10 minutes or dried at 50 to 100xc2x0 C. for about 1 to about 10 minutes. Thereafter, the surface of the uncured paint film is coated with the above powdery paint by methods such as electrostatic powder coating and friction electrification powder coating so that the total thickness of the resultant paint films will be in the range of 20 to 100 xcexcm, favorably 30 to 80 xcexcm. Then, both paint films are simultaneously cured by heating at 120 to 180xc2x0 C. for about 10 to about 50 minutes.
(Effects and Advantages of the Invention)
The present invention can provide a novel (meth)acrylate ester-based resin composition which, for example, exhibits various good properties such as weather resistance, heat resistance, water resistance, acid resistance, alkali resistance, warm water resistance, impact resistance, processability, flexibility, hardness, elongation, transparency, luster, fleshy property, mirroring property, pigment dispersibility, and driability when being used, for example, as crosslinking type paints, adhesives, pressure sensitive adhesives, and fiber-processing materials, and has so low a resin viscosity as to be utilizable as a resin for coping with environmental pollution of such as low-VOC paints.
Hereinafter, the present invention is more specifically illustrated by the following examples of some preferred embodiments in comparison with comparative examples not according to the invention. However, the invention is not limited thereto.
Incidentally, hereinafter, the xe2x80x9cweight part(s)xe2x80x9d might be referred to simply as xe2x80x9cpart(s)xe2x80x9d for convenience"" sake.
In addition, hereinafter, in the case where the notation form xe2x80x9c(A/B)xe2x80x9d is used as a notation for indicating a classification of the crosslinking system, A is a polymer and B is a crosslinking agent.
(Methods for Measuring Numerical Values of Properties of Resin)
(Measurement of Viscosity)
As to the solvent type resin, the viscosity was measured by Gardner""s viscosity measurement method (using a Gardner-Holdt bubble viscometer, at 25xc2x0 C.).
As to the resins other than the solvent type resin, the viscosity was measured at 30 minxe2x88x921, 25xc2x0 C. with a BM type viscometer (produced by Tokyo Instruments Co., Ltd.), when the rotor was selected according to the viscosity.
(Nonvolatile Content)
About 1 g of specimen was weighed out and then dried in a hot-air drying oven of 105xc2x0 C. for 1 hour. The resultant drying residue was taken as the nonvolatile content, and its ratio to what the weight of the specimen had been before the drying was indicated by weight %.
(Volume-average Particle Diameter)
The volume-average particle diameter was measured with a particle diameter measurement apparatus by the dynamic light scattering method (NICOMP Model 370, produced by HIAC/ROYCO INSTRUMENTS DIVISION Co., Ltd.).
(MFT: Minimum Film Formation Temperature)
The specimen was coated onto a glass plate (which was put on a thermal gradient testing machine) by using an applicator of 0.2 mm and then dried, and the temperature (xc2x0 C.) at which the resultant coating film on the glass plate cracked was taken as the MFT.
(Number-average Molecular Weight: Mn)
The number-average molecular weight was measured by HLC-8020 Model gel permeation chromatography (using TDKgel G-5000HXL and TSKgel GMHXL-L in tandem; produced by TOSOH Corporation) (in terms of polystyrene).
(Acrylic Polyol/polyisocyanate Crosslinking System)